For accurate placement of stents at a target location within the body of the patient, it is customary to use radiological techniques, for which the stent must be such that it can be imaged. The biologically compatible materials from which stents are usually made (stainless steel and nickel-titanium shape memory alloy) are not as opaque to x-rays as one would wish, for the purpose of radiologically tracking their progress through the body to the precise location for deployment, so it is often useful to equip such stents with one or more radiopaque markers of a biologically compatible material that is more opaque, to the medical x-rays used by the radiologist, than the material of the stent as such. Noble metals such as gold or silver, platinum or palladium can be used, but tantalum is particularly attractive for use with nickel-titanium stents because it is of similar electrochemical potential thereby reducing to acceptable levels the rates of electrochemical corrosion that follow from galvanic battery action within the electrolyte provided by the bodily fluid in the lumen in which the stent is located.
In above mentioned WO2002/015820 welding techniques are used to ensure that markers cannot separate from a nickel-titanium stent, after deployment of the stent. Thus, the marker is in full electrically-conductive contact with the metal of the stent. Breaking that full electrical contact would be useful, to reduce the rate of galvanic dissolution of metal after deployment of the stent, but a way would need to be found, to join together the marker and the stent securely enough to eliminate the risk of separation after deployment, in substitution for the currently used joining method, welding. The present invention takes up this challenge, and offers a solution.